def _mq_callback(self, message):
        """ wraps call of abstract method with try/except 
        in case exception breaks the abstract method, this method:
        - catches the exception
        - logs the exception
        - marks unit of work as INVALID"""
        try:
            single_session_collection = CollectionContext.get_collection(self.logger, COLLECTION_SINGLE_SESSION)
            raw_data = RawData(message.body)
            query = {AbstractModel.DOMAIN_NAME: raw_data.get_key()[0],
                     AbstractModel.FAMILY_USER_PROFILE + '.' + AbstractModel.SESSION_ID: raw_data.get_session_id()}
            document = single_session_collection.find_one(query)

            if document is None:
                # insert the record
                session = SingleSessionStatistics()

                # input data constraints - both session_id and user_id must be present in MQ message
                session.composite_key(raw_data.get_key()[0], time_helper.raw_to_session(raw_data.get_key()[1]))
                session.set_session_id(raw_data.get_session_id())
                session.set_ip(raw_data.get_ip())
                session.set_total_duration(0)

                session = self.update_session_body(raw_data, session)
                self.add_entry(session, 0, raw_data)
                self.performance_ticker.increment_insert()
            else:
                # update the click_xxx info
                session = SingleSessionStatistics(document)

                session = self.update_session_body(raw_data, session)
                duration = raw_data.get_key()[1] - time_helper.session_to_epoch(session.get_key()[1])
                session.set_total_duration(duration)

                index = session.get_number_of_entries()
                self.add_entry(session, index, raw_data)
                self.performance_ticker.increment_update()

            if time.time() - self._last_safe_save_time < self.SAFE_SAVE_INTERVAL:
                isSafe = False
            else:
                isSafe = True
                self._last_safe_save_time = time.time()

            single_session_collection.save(session.get_document(), safe=isSafe)
            self.consumer.acknowledge(message.delivery_tag)
        except AutoReconnect as e:
            self.logger.error('MongoDB connection error: %r\nRe-queueing message & exiting the worker' % e)
            self.consumer.reject(message.delivery_tag)
            raise e
        except (KeyError, IndexError) as e:
            self.logger.error('Error is considered Unrecoverable: %r\nCancelled message: %r' % (e, message.body))
            self.consumer.cancel(message.delivery_tag)
        except Exception as e:
            self.logger.error('Error is considered Recoverable: %r\nRe-queueing message: %r' % (e, message.body))
            self.consumer.reject(message.delivery_tag)
class TestSingleSessionStatistics(unittest.TestCase):
    def setUp(self):
        self.obj = SingleSessionStatistics()

    def tearDown(self):
        del self.obj

    def test_key(self):
        domain_name = "test_name"
        correct_timestamp = "20110101_161633"
        self.obj.composite_key(domain_name, correct_timestamp)
        temp = self.obj.get_key()
        assert temp[0] == domain_name
        assert temp[1] == correct_timestamp

    def test_session_id(self):
        value = "value_1234567890"
        self.obj.set_session_id(value)
        temp = self.obj.get_session_id()
        assert temp == value

    def test_os(self):
        value = "Windows MS PS 7.0.0.0.1.1.2"
        self.obj.set_ip(value)
        temp = self.obj.get_ip()
        assert temp == value

    def test_browser(self):
        value = "FF 3.4.5.6.7.8.9"
        self.obj.set_ip(value)
        temp = self.obj.get_ip()
        assert temp == value

    def test_ip(self):
        value = "100.100.200.200"
        self.obj.set_ip(value)
        temp = self.obj.get_ip()
        assert temp == value

    def test_screen_res(self):
        value_x = 1080
        value_y = 980
        self.obj.set_screen_res(value_x, value_y)
        temp = self.obj.get_screen_res()
        assert temp[0] == value_x
        assert temp[1] == value_y

    def test_language(self):
        value = "ca-uk"
        self.obj.set_language(value)
        temp = self.obj.get_language()
        assert temp == value

    def test_country(self):
        value = "ca"
        self.obj.set_country(value)
        temp = self.obj.get_country()
        assert temp == value

    def test_total_duration(self):
        value = 123
        self.obj.set_total_duration(value)
        temp = self.obj.get_total_duration()
        assert temp == value

    def test_number_of_entries(self):
        value = 12
        self.obj.set_number_of_entries(value)
        temp = self.obj.get_number_of_entries()
        assert temp == value